Publikasjoner
NIBIOs ansatte publiserer flere hundre vitenskapelige artikler og forskningsrapporter hvert år. Her finner du referanser og lenker til publikasjoner og andre forsknings- og formidlingsaktiviteter. Samlingen oppdateres løpende med både nytt og historisk materiale. For mer informasjon om NIBIOs publikasjoner, besøk NIBIOs bibliotek.
2011
Forfattere
Trond RafossSammendrag
ClimaRice II is exploring the potential for use of mobile technologies in the context of climate change adaptation in agriculture. Modern mobile telephone technology is a key component of the ongoing communication revolution which in turn has great potentials for social change and development. The Indian telecommunication industry is the world's fastest growing industry with 811.59 million mobile phone subscribers as of March 2011. Most farmers are already using mobile phones for various day to day needs, but the technology has a wider potential in supporting their main profession; agriculture. Linking mobile technology with adaptation measures developed in ClimaRice projects could form new and powerful measures to meet the threats from climate change and provide support in sustaining rice production.
Forfattere
Liv OstremSammendrag
Forsøksserien vart starta i 2005 for å sjå på avling og fôrkvalitet ved ulike slåtte- og beiteregime til aktuelle utanlandske raisvingelsortar (HYKOR og FOJTAN; italiensk raigras x strandsvingel, PERUN og FELOPA; italiensk raigras x engsvingel), ein norsk kandidatsort av raisvingel (FuRs9806; fleirårig raigras x engsvingel), marknadssortar av fleirårig raigras (NAPOLEON og BARISTRA) og ein norsk hybridraigrassort (FENRE; eittårig x fleirårig raigras). Det var etablert felt i Møre og Romsdal, Sogn og Fjordane, Rogaland, Vest-Agder, Akershus, Oppland, Hedmark, Sør-Trøndelag, Nord-Trøndelag og Nordland. Felta hadde to slåtteregime med to gjentak; eit med minst 3 slåttar pr år og eit simulert beiteregime med 4-5 slåttar pr år. I engåra vart felta gjødsla i samsvar med vanleg gjødsling i området. I første engåret vart alle slåttane analyserte med NIRS.Ti felt vart hausta i tre år, og middels tørrstoffavling (kg ts) for treslåttsregimet var 1108 kg ts (1037-1185 kg ts) for tre slåttar i tre år mot 877 kg ts (838-952 kg ts) som snitt for fem slåttar. I begge slåtteregima gav Hykor størst avling. Fojtan, ein annan strandsvingel-type, gav i begge regima 89% av Hykor som snitt over tre år. Perun og Felopa er begge raigrastypar med vekstform som ligg mellom foreldreartane. Avlingsmessig var Perun mest like god som Hykor med store avlingar dei to første åra. På grunn av dårlegare overvintringsevne var det relativ stor reduksjon tredje engåret. Felopa gav i begge regima 94% av Perun som snitt over tre år. Kandidatsorten FuRs9806 hevda seg relativt betre i beiteregimet enn med tre slåttar, og i snitt over tre år gav FuRs9806 94% og 100% i høvesvis slåtte- og beiteregimet samanlikna med Napoleon fleirårig raigras. Dei to sortane av fleirårig raigras, Napoleon og Baristra, gav 93% og ca 90% i høvesvis slåtte- og beiteregimet samanlikna med Hykor. Baristra var i begge regima avlingsmessig den jamnaste sorten over år. Hybridraigrassorten Fenre gav 96% og 93% samanlikna med Hykor for høvesvis slåtte- og beiteregimet.Fôreiningskonsentrasjonen (FEm) varierte mykje mellom dei 14 felta, og sum fôreiningsavling (kg ts x FEm) i første engår vart redusert med mellom 10,1% og 16,4% samanlikna med ts-avlinga når tre slåttar vart justert for FEm. Tilsvarande reduksjon for beiteregimet var frå 2,8% til 9,1%. I treslåttsregimet vart fôreiningsavlinga mest redusert i andre slått (17% i snitt), medan både første- og tredjeslått hadde 10% reduksjon. I beiteregimet var fôreiningsavling lik tørrstoffavling i førsteslåtten men vart redusert med opp mot 10% i dei tre neste slåttane samanlikna med ts-avlinga.Mineralbalansen i fôret er viktig, og forholdet mellom kalium (K) og magnesium (Mg) + kalsium (Ca) bør ikkje vera større enn 2,2. I forsøksserien varierte dette mykje, og berre seks av 14 felt var under 2,2 i førsteslåtten både i slåtte- og beiteregimet. I snitt for dei 14 felta var forholdstalet 2,05 og 2,28 for førsteslåtten i høvesvis slåtte- og beiteregimet. N/S-forholdet bør vera under 14 for at proteinsyntese i vom skal fungera optimalt, og dette var bra i alle felta. I førsteslåtten var forholdstalet 10,4 og 11,3 for høvesvis slåtte- og beiteregimet.Bladgras som raigras og raisvingel har potensiale til å gi god avling med god fôrkvalitet dersom overvintringstilhøva ligg til rette for å nytta sortar av desse artane. Tørrstoffavling i seg sjølv vil dermed ikkje vera avgjerande med mindre denne avlinga har betre fôrkvalitet enn ei vanleg timotei-engsvingelblanding, evt. at areal med raigras eller raisvingel blir nytta til beiting som desse artane toler godt.
Sammendrag
Gjennom prosjektet "Sikker og miljøvennlig bekjempelse av bladskimmel i løk, salat og agurk i Norge" har vi i perioden 2006 til 2009 hatt som hovedmål å få til effektiv og miljøvennlig bekjempelse av bladskimmel ved å utvikle varslingsstrategier for disse sjukdommene. Prosjektet har vært finansiert av Norges forskningsråd, Fondet for forskningsavgift på landbruksprodukter, Forskningsmidler over Jordbruksavtalen og dyrkermiljøene for isbergsalat, vårløk, kepaløk og frilandsagurk. Forekomst av bladskimmel er vanskelig å forutse og varierer fra år til år, både i utbredelse og tidspunkt for når angrepene oppstår. Problemene med bladskimmel er størst på ettersommeren og vanligst forekommende i områder med intensiv produksjon. Relativt små angrep av bladskimmel kan medføre store tap i kulturer hvor bladene utgjør en viktig del av avlingen, som i salat og vårløk. I agurk og kepaløk kan angrep av bladskimmel medføre at bladene visner, og dermed føre til store avlingstap. Bladskimmel forårsakes av sopplignende organismer som er svært vertsspesifikke og sjelden smitter mellom ulike plantefamilier. Alle arter av bladskimmel produserer ukjønna sporer som spres i lufta. Vi har vist i forsøk at sporer fra salat- og agurkbladskimmel har ulik evne til å overleve i luft. Etter tre timers eksponering i sol var alle sporene fra salatbladskimmel drept, mens sporene kunne overleve ca ett døgn i skygge. Sporer fra agurkbladskimmel overlevde ca ett døgn i sol, mens sporene kunne overleve i flere døgn i skyggen. Det er derfor sannsynlig at levedyktige sporer av agurkbladskimmel kan spres i luft over lange avstander. De fleste arter av bladskimmel kan også danne hvilesporer som kan overleve flere år i jorda. Slike hvilesporer har trolig liten betydning som smittekilde for agurkbladskimmel i Norge, mens det er mer usikkert hvor viktig dette er i løk. I salat anses hvilesporer å være av større betydning. Vekstskifte bør derfor utgjøre en viktig del av bekjempelsesstrategien mot bladskimmel. Bladskimmel har en svært god tilpasningsevne både når det gjelder å bryte resistens i vertplanter og ved å utvikle resistens mot kjemiske preparater. Det vil derfor være viktig å begrense angrep av bladskimmel samtidig som unødvendig bruk av kjemiske preparater unngås. En rekke feltforsøk med utprøving av fungicider mot bladskimmel er gjennomført av Norsk landbruksrådgiving hos lokale produsenter, og flere av de prøvde midlene hadde god effekt mot bladskimmel i salat, vårløk og agurk. Det er imidlertid påvist en tydelig tendens til redusert effekt av Aliette 80 WG og det plantestyrkende preparatet Resistim i enkelte isolater av salatbladskimmel, noe som indikerer at resistensproblemer er i ferd med å oppstå. Flere varslingsmodeller for salatbladskimmel og løkbladskimmel er testet i prosjektperioden, og to modeller er nå tilgjengelige i VIPS (http://www.vips-landbruk.no/). Varsling av bladskimmel er basert på å forutse perioder med klimatiske forhold som er gunstige for sporulering og infeksjon av patogenet. Varslingsmodellene kan brukes til å vurdere når en bør intensivere overvåking av felt med hensyn på angrep av bladskimmel, og til å bestemme når og hvor ofte det vil være behov for å sprøyte mot bladskimmel. For agurkbladskimmel finnes det ikke noen aktuell modell, men for denne sjukdommen vil overvåkning av når smitten først kommer inn i et område med agurkproduksjon være mer hensiktsmessig enn å bruke en varslingsmodell til å vurdere sprøytetidspunkt. Ved bruk av sporefeller som suger inn luft kan eventuell luftbåren smitte fanges og identifiseres ved bruk av PCR. I flere tilfeller har det lykkes å påvise DNA fra agurkbladskimmel i sporefellene før sjukdommen ble påvist i felt.
Sammendrag
Nematodes, commonly known as round worms, are the most common multicellular animals on planet Earth. After 1000 million years of evolution members of the phylum Nematoda have a high bionomic diversity. As habitants of the soil and rhizosphere nematodes are involved en energy fluxes, and affect carbon and nutrient cycles. As plant parasites, either alone or in synergism with other pathogens, nematodes are responsible for plant disease complexes and major crop losses. A growth depression in a field of potato (Solanum tuberosum) cv. Saturna [resistant to pathotype Ro1 of potato cyst nematode (PCN) Globodera rostochiensis], suggestive of potato cyst nematode damage, was detected in Grue, eastern Norway. Analyses of soil samples did not detect PCN, but demonstrated the occurrence of a large number of lesion nematodes Pratylenchus penetrans .Tubers from the depressed part of the field had severe symptoms similar to those caused by the common scab bacterium Streptomyces scabies. Potato yield was reduced by 50% in the affected area of the field. Transect-sampling showed plant growth to be negatively correlated with densities of P. penetrans and suggested a damage threshold of potato to the nematode of 100 specimens per250 g of soil. Common scab (Streptomyces scabies) occurred frequently in the affected area. P. penetrans was present in roots, underground stems, stolons and tubers. Tubers from the depressed part of the field had severe symptoms similar to those caused by the common scab bacterium. In tubers, nematodes were detected inside cross-lesions typical symptoms of common scab, and occurred also in the outermost 0.5 mm tissue associated with such lesions. In pots with sterile sand, micro-tubers of potato cv. Saturna, produced from meristems, were grown in a green-house infected with, P. penetrans, S. scabies, and a combination of P. penetrans and, S. scabies. P. penetrans alone induced tuber lesions similar to those of common scab. Also, the combined inoculation of the bacterium and the nematode seemed to enhance symptom expression. Similar scab symptoms, in connection with lesion nematode infections, have been observed on potato tubers cv. Oleva, which also is relatively tolerant to common scab. Symptomatic tubers cv. Saturna first stored at 4o C for 20 weeks were transferred to pots with sterile sand and grown for 3 months in the green-house. In these cultures P. penetrans was first detected in soil 8 weeks after planting. Examination at harvest of soil, roots, stolons, tubers demonstrated symptoms typical of P. penetrans. Interestingly, P. penetrans survives storage of potatoes, from which new infections may develop. Hence, potato tubers do appear to be an important means for the spread of P. penetrans to new areas. The fact that the symptoms induced by this nematode may be mistaken for symptoms of common scab suggests that the frequency of S. scabies might have been overestimated in regular surveys. Infections by P. penetrans have important implications for scab control. This pertains in particular to recommended maintenance of high soil moisture at and during 4-9 weeks after tuber set. If symptoms are related to nematode infection rather than to the scab bacterium, this recommendation would allow for a rapid build-up of lesion nematodes resulting in a decrease in both yield and marketability of the tubers. Further studies are needed to investigate the extent of this problem.
Forfattere
AnneLise Chapman Kjell Inge Reitan Celine Rebours Øyvind StrandSammendrag
Integrated multi-trophic aquaculture (IMTA) is a strategy to utilize all resources in an aquaculture system (i.e. primarily fish farms in Norway) in a holistic manner. In Norway, farmed salmon is fed on high-quality fish feed, mainly based on wild catches. Therefore, optimizing the utilization of this type of primary resource is economically, ecologically and socially sensible. To develop relevant IMTA systems in Norway, new species should be integrated into sea-based farming of salmon, thereby providing a method for re-cycling nutrients in the culture system while ameliorating potential environmental problems. Inorganic nutrients from fish farms can be taken up by primary producers such as seaweeds (Neori et al. 2004). In addition to nutrients, seaweeds also assimilate CO2 from surrounding waters, thus producing oxygen. Through both mechanisms - excess nutrient assimilation and oxygen production - seaweed farming will improve the water quality of the locality. Organic particles originating from the fish farm (e.g. from faeces or excess fish feed) can be cleared from the water by filter-feeding organisms such as bivalves. In addition, deposit feeding species (e.g. holothurians or other echinoderms) could be added to an IMTA system to re-cycle particles deposited under the farms at the sea floor. However, the placement and design of integrated farming systems requires an understanding of the transport and distribution of nutrients and particles in the marine system. Co-location of farms may lead to water transport reduction from frictional forces, and consumption of compounds vital for the farmed organisms (e.g. nutrients and oxygen) may cause depletion that affects the production capacity of the farm (Aure et al. 2007). Any reduction in water transport due to "shading" and consequently potential production losses need to be considered when addressing the benefits gained from IMTA. IMTA systems will contribute to our ecological understanding in the planning process of aquaculture operations and increased sustainability of the aquaculture industry as a whole. This is important for the continued development of the aquaculture industry in Norway.
Forfattere
Berit Nordskog Trond Rafoss Ragnhild Nærstad Ingerd Skow Hofgaard Halvard Hole Oleif Elen Guro BrodalSammendrag
Forecasting models for prediction of diseases and pests in crop plants are helpful tools in decision support systems for crop management. Correct use of pesticides may result in optimal effect, increased yield and better quality of the crop, while minimizing the environmental strain and costs. In Norway, a range of decision support systems for diseases, pests and weeds are available through the internet service VIPS (www.vips-landbruk.no). The reliability of disease and pest forecasts depends on robust forecasting models and relevant weather data. Although weather data are collected from a network of 80 weather stations located in agricultural production areas in Norway, many farms are remotely located from a weather station. The accuracy of forecasts relies on distance and geographical variation from the farm site to the nearest weather station. Forecasts for pest or diseases can be tailored to fit the local conditions at a farm site by use of weather forecasts and radar measured rainfall. The use of this system will be of particular interest to farms located far from the nearest weather station. Also, locally adapted forecasts for pest or diseases promote a sense of ownership and personal interest in the forecasting systems provided. The Norwegian Meteorological Institute provide weather forecasts on a 4x4 km spatial resolution in rural areas on a 1 hour timescale, while radar measured rainfall has a 1x1 km spatial resolution on a 15 min time scale. These data are currently connected to the existing weather stations to predict warnings ahead of time. The new approach is to adapt these data to individual farm sites. Previous tests have shown that weather prognosis for rainfall is less accurate than weather prognosis for temperature, wind, air humidity and radiation. Estimated rainfall will therefore be based on radar measurements. As part of a pilot project, the use of farm scale forecasts to predict development of plant diseases were tested at 35 farms in the Solør-Odal district in Norway in 2010 and 2011. Preliminary results show that late-blight forecasts produced on a farm scale often differ from forecasts based on data from the nearest weather station, proving the significance of the local approach in farm scale forecasting. Predictions of DON (deoxynivalenol) concentration in oats at harvest based on farm scale weather data, compared to predictions based on weather data from the nearest weather station will also be studied. Future aspects will be to work towards an improved system where farmers throughout Norway can register their farm and automatically have access to a range of pest and disease forecasts based on site specific weather data.
Sammendrag
Downy mildew, caused by Hyaloperonospora parasitica s.l., represents an increasing threat to Norwegian production of cruciferous vegetable crops. Although the pathogen has been present in Norway for over a century, the intensified production regimes of field vegetables has contributed to an increase in disease incidence and severity. The project “Effective and sustainable control strategies for downy mildew in rocket, broccoli and cauliflower” were initiated by vegetable growers and financed by the Norwegian Research Council, “Jordbruksavtalen”, “Fondet” and vegetable growers for the period 2009-2011. As part of the project we have surveyed the presence of downy mildew in cruciferous crops and weeds, tested possible cross inoculation between different cruciferous crops and weeds, and tested how long detached spores can survive in air. The survey of downy mildew incidence in cruciferous crops (mainly rocket, broccoli and cauliflower) and weeds were performed by local extension officers in the Counties Buskerud, Rogaland, Vestfold, østfold, and Hedmark. In addition, 65 growers were asked to survey and report findings in their fields. During the project period downy mildew incidence was mainly observed in wild rocket (Diplotaxis tenuifolia) and broccoli, while a few incidences of downy mildew were reported in swede, oil seed rape and the weed Sheperd’s purse (Capsella bursa-pastoris). The host range of isolates collected in the survey was assessed on a selection of cruciferous species. Seedlings of wild rocket (‘DI902’), cultivated rocket (Eruca sativa), cauliflower (‘Freedom’), broccoli (‘Ironman’), oil seed rape (‘Valo’) and swede (‘Vige’) were inoculated by spraying the cotyledons with a spore suspension. One week after inoculation, the seedlings were incubated over-night at high RH and scored for positive infections by observation of visible sporulation on the cotyledons. Preliminary results show that downy mildew from oil seed rape can infect swede, cauliflower and broccoli. Isolates from broccoli were partly virulent on cauliflower. An isolate from swede were virulent on broccoli, while an isolate from rape were virulent on cauliflower, broccoli and swede. An isolate from Sheperd’s purse was virulent on broccoli. Isolates from wild rocket were not virulent on any of the other plants in the trial. The results indicate a risk of cross infection between different cruciferous species, although also supporting the ongoing discussions on dividing H. parasitica into separate species. The possibility of long distance dispersal of viable spores depends on how long the spores can survive in free air. Spores from freshly sporulating rocket seedlings were transferred to filter paper and exposed to solar radiation or in shade. Preliminary results show that spores were not able to germinate after 6 hours exposure to the sun, while shaded spores were able to survive for 24 hours or more. These results will be included in the development of a forecasting model for downy mildew on cruciferous crops.
Sammendrag
Colletotrichum acutatum causes black spot in strawberry (Fragaria × ananassa), but it has also been isolated from 30 other cultivated and non-cultivated plant species in Norway, including almost all fruit and berry crops. Bitter rot, which is caused by C. acutatum, is a severe disease in sweet and sour cherry and apple. We have studied the possibility of cross infection of isolates from other hosts and the potential aggressiveness of these isolates on strawberry. Molecular analyses (AFLP) have shown that isolates collected in Norway could be separated into three major phylogenetic groups in which isolates collected from either Prunus spp., Malus domestica or Fragaria × ananassa predominated. Experiments were carried out under laboratory, greenhouse and field conditions, and strawberry fruits, leaves and stolons were inoculated. All experiments showed that isolates originating from the Fragaria group was much more aggressive than those from the other two groups. If detached strawberry fruits were wounded at time of inoculation, isolates from all groups developed black spot, but disease development went much slower for isolates from the Prunus or Malus groups. If not wounded, there was no or hardly any disease development caused by isolates from the latter two groups. On whole plants inoculated in the greenhouse, isolates in the Fragaria group developed an incidence of 27 to 28 % flower and fruit infections compared to 0 to 4 % for isolates from the other two groups. Under field conditions, Fragaria group isolates developed 50 to 70 % more infected fruit than the others at harvest. On stolons, we inoculated by wounding, and differences in aggressiveness between isolates were only minor. On strawberry leaf laminas, we observed that the ability to colonize the leaf surface was much larger for isolates from the Fragaria group compared to those from the other two groups. However, planting healthy strawberry transplants adjacent to infected sweet cherry trees resulted in latent infections of C. acutatum on strawberry leaves (but no visible infections on fruits), indicating that cross infection between host species may occur under field conditions.
Forfattere
Mats HøglindSammendrag
To develop mechanistic models for winter survival of grasses under climate change, more knowledge is needed of photosynthetic activity at low irradiance and temperature. Photosynthetic activity of small stands of Lolium perenne was continuously studied for up to two weeks under low photosynthetic photon flux density (PPFD) in the air temperature range from -3°C to +9°C. The photosynthetic rate of plants growing at 2, 6 and 9°C was similar at 120 µmol m-2 s-1 PPFD but the rate increased with increasing PPFD at all temperatures, particularly 9°C. Light saturation of photosynthesis was reached at approx. 300 µmol m-2 s-1 at 2 and 6°C, and at approx. 600 µmol m-2 s-1 at 9°C. At 300 µmol m-2 s-1, the CO2 exchange rate (CER) at 2°C was approx. 60% of that at 9°C. When the temperature increased gradually from 0°C at start to +5°C at the end of the 8-h photoperiod, CER decreased by about 20% compared with that at constant 5°C. Changing the temperature from constant +5°C to a diurnal variation between -2 and +2 °C gradually decreased daytime CER to approx. 10% after five days, partly due to leaf area losses (~50% loss) when the poorly acclimatised plants were exposed to frost. At start of the photoperiod at -2°C CER was negative, but became slightly positive when temperature exceeded -1°C after two hours. Total daily photosynthesis was negative due to night-time respiration in this treatment. Soil heating to avoid freezing when the diurnal air temperature fluctuated between -3 and + 3°C had no effect on CER at this low PPFD level (150 µmol m-2 s-1). In contrast to the -2/+2°C treatment, total daily photosynthesis was slightly positive in the -3/+3°C treatment, where the plants were better acclimatised to frost. Increasing the CO2 concentration from 350 to 600 µmol mol-1 had no effect on CER at 2 and 6°C, but increased it by 20% at 9°C. The data indicate that the minimum temperature for photosynthesis in the cultivar studied is about -4°C. The results can be applied in different photosynthesis models.
Forfattere
Tor J. JohansenSammendrag
Production of healthy, vigorous potato plants and a high yield of good quality under varied environmental conditions require quality seed tubers. Quality may be divided in two important factors, tuber health and physiological quality. Physiological quality (number and vigour of sprouts and stems, growth and yield potential) is determined by the size of the seed tuber, the physiological status of the seed and interactions between these two factors. The physiological status of the seed is usually called physiological age. This may be defined as “the stage of development of a tuber, which is modified progressively by increasing chronological age, depending of growth history and storage conditions” (Struik and Wiersema 1999, Seed potato technology). The sequence of stages of development are dormancy, apical sprouting, normal sprouting with a few or multiple branched sprouts, senility and finally incubation with direct formation of daughter tubers on the seed tuber. Each stage has a strong influence on vigour and yield potential of the seed. Temperature is the most important environmental factor that affects physiological age in seed potatoes, either during growth of the mother plant, or during storage. Unfortunately, physiological age is hard to measure directly, and indirect methods, based on sprout development, sprout characteristics and sprouting capacity are normally used. In Norway, several studies of the impact of geographic origin, growth temperatures, day-lengths, and pre-storing temperatures on vigour and yield potential have been performed the last10 years. One of the aims has been to study the “northern vigour claims”, which implies superiority of seed produced in northern latitudes over seed produced in southern latitudes. In summary the results showed: Low temperature (9 ºC) gave a small but positive effect on progeny growth vigour and yields compared to a higher temperature (15 ºC) in cv. ‘Troll’. Day-length (12 or 24 hrs) did not affect the results significantly. In a study with average temperatures of 9, 15 and 18 ºC, 12 and 24 hrs day-lengths, the physiologically oldest tubers originated from the lowest growth temperatures. In a three-year field study at distant sites in Norway (lat. 59-70) the results showed no superiority of seed from any latitude, regarding vigour and yields. In a controlled climate study at 9, 15 and 21 °C, results showed that dormancy may be shortened by low grow temperatures, and similarly by low post-harvest temperatures (4 °C). The scientific fundament of “northern vigour” is still not clear, but as a statement it may call attention to the generally good quality of northern seed.